<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="text" placeholder="请输入0-100之间的整数" id="i1">
<input type="button" value="猜一猜" onclick="f()">
<div>结果:<span></span></div>

<script>
  //得到0-100随机数字
  let x = parseInt(Math.random()*101);
  let i = 0;
  function f() {
    i++;
    let i1 = document.querySelector("#i1");
    let s = document.querySelector("span");
    if(isNaN(i1.value)){
      s.innerText = "输入错误!";
      return;
    }
    if (i1.value > x) {
      s.innerText = "猜大了！";
    } else if (i1.value < x) {
      s.innerText = "猜小了!";
    } else {
      s.innerText = "恭喜你猜对了!用了"+i+"次.";
      i=0;
      x = parseInt(Math.random()*101);
    }
  }
</script>

</body>
</html>